Grease pencil and Unity
Short version: Render it out and make a Sprite Animation.
Long version:
Click on the Faces, where you draw the with your animation, of your Object.
Say &quot;Object by selected&quot;. Now you have a extra Object.
Take the Camera and fix it to your Animation.
Render the whole GreasePencil Animation out. Just the GreasePencil. Use the Transparent Shader.
Create a Sprite Image, based on your rendered images.
Import your everything in Unity.
Give your Mesh the normal Materials and the FaceObject is a Sprite Image.
I learned it here.
https://www.udemy.com/course/blender-28-game-character-creation/learn/lecture/14405776#notes
I hope that helped:)